[JNG] Incorrect 1-bit alpha

[Solovei95]

New JNG bugs:

convert img1.png -define png:bit-depth=1 -channel alpha -threshold 100% -depth 12 -compress zip -quality 95080 -sampling-factor 4:2:2 img1.jng
Result: binary alpha channel, but threshold value does not works
convert img1.png -define png:bit-depth=1 -channel alpha -black-threshold 100% -depth 12 -compress zip -quality 95080 -sampling-factor 4:2:2 img1.jng
Result: no effect
convert img1.png -define png:bit-depth=1 -channel alpha -white-threshold 100% -depth 12 -compress zip -quality 95080 -sampling-factor 4:2:2 img1.jng
Result: white image, with alpha channel

This image:
http://img849.imageshack.us/img849/8961/img1m.png
Version: 6.7.4.4

[glennrp]

The first example works for me, if I use -threshold 50% instead of -threshold 100%.
The other two both cause a segfault in the JNG encoder for me, with IM-6.7.4-4,
which seems to be a bug in the JNG encoder (some problem with the use of
12-bit image; changing -depth 12 to -depth 8 makes them not crash, but it
appears that the black-threshold and white-threshold are being applied to
the main image, not to the alpha channel)

[Solovei95]

В версии Q16 заметил баг: числа колеблются от 0 до 6554% (усеченный 65536).

[Solovei95]

Не, вообще баг в ImageMagick...

[Solovei95]

Причем знак % совсем не % в .bat файлах...
Совсем не...

Работает от 0 до 65535

[glennrp]

В версии Q16 заметил баг: числа колеблются от 0 до 6554% (усеченный 65536).

That may have something to do with the use of -depth 12.

[glennrp]

The problem with -black-threshold and -white-threshold ignoring the -channels option is fixed in SVN revision 6341
(will be ImageMagick-6.7.4-5).

[Solovei95]

Скоро будет эта версия финальной?
У меня уже проблемы с компиляцией т.к. нету папки VisualMagick.

[glennrp]

Скоро будет эта версия финальной?
У меня уже проблемы с компиляцией т.к. нету папки VisualMagick.

Yes, soon there will be a tar, zip, 7z release in the ftp directory and Windows
executables, etc. It depends on Cristy's schedule for running regression tests
and making the files, but I would be surprised if it's more than a week from now.